Why Does My Water Pump 'hunt'?

[simon43]

At my 10-room hotel, I have a well (8 metres depth) and I use a pump to pump the water up to a holding tank on a small tower, some 8 metres in height. I then use a second (and powerful) pump at the base of this tower to pump the water into the guest bathrooms. Both pumps are well specced for the depths and heights concerned.

But both pumps 'hunt'!! That is, they contimnually switch off and on throughout the day. Of course, when guests use the bathrooms, there is a demand for water and the pumps switch on. But when there is no (apparent) demand for water, the well pump in particular, hunts all the time. Apart from the annoying noise, I have to replace the electrical switch contacts on a regular basis.

Does anyone else have experience of this type of problem? Any solutions???

Simon

[Farma]

First thing I would do is look for obvious leaks.

[Ratsima]

Do you have a pressure tank (captive air tank) on either pump?

[Crossy]

Yup, check for leaks, not always easy.

How is the well pump controlled, do you have two float switches (upper limit turns the pump off, lower limit turns it on) or just one (a receipe for hunting).

Does the other pump have a pressure reservoir, if so check the tank has air. There are other threads on this type of pump hunting, try a search

[lopburi3]

Or no switch on the well pump and each time the tank float allows a dribble of water out the pressure lowers and it starts?

[Crossy]

Or no switch on the well pump and each time the tank float allows a dribble of water out the pressure lowers and it starts?

Duh, hadn't thought of that implementation

I always assumed that the use of float switches was the 'correct' way to do it, using the tank as a big buffer and not firing up the well pump until the tank is say 30% empty. But of course TiT.

[cmsally]

Strange, have never know a well pump to "hunt".

We have a float switch and water has to decrease by about 20% before it kicks in.

We have had problems with outlet pump "hunting" which was solved by using the pressure tank.

For both pumps to be a problem sounds like float not adjusted correctly and also a leak/s.